Synthesis of microcrystalline cellulose from oil palm empty fruit bunches through sequential chemical processing

Abstract

• SEM revealed a smoother and more uniform particle morphology. • Elemental analysis confirmed the impurity reduction and cellulose enrichment. • FTIR indicated the removal of lignin and hemicellulose groups. • The XRD analysis revealed an increase in cellulose crystallinity. • The thermal analysis showed improved thermal stability. Oil palm empty fruit bunches (OPEFB), a major agricultural residue of the palm oil industry, represent an underutilized lignocellulosic resource for value-added material production. Converting this biomass into Microcrystalline Cellulose (MCC) provides a sustainable waste valorization approach. In this study, we developed a method for synthesizing MCC from OPEFB using NaOH–KOH treatment and H₂O₂-CH₃COOH purification. The physical, chemical, and thermal properties of the samples were evaluated using various characterization techniques. Scanning electron microscopy revealed surface fragmentation and fibril exposure, with the particle size reducing from 770.55 ± 12.81 µm to 38.39 ± 13.18 µm. Energy-dispersive X-ray spectroscopy confirmed the removal of non-cellulosic elements and the dominance of C and O in the final MCC. Fourier transform infrared spectroscopy showed intensification of cellulose bands and elimination of lignin and hemicellulose peaks. X-ray diffraction analysis showed an increase in the crystallinity index from 31.18 ± 2.28% to 74.23 ± 1.81%. Thermogravimetric analysis revealed enhanced thermal stability, with the decomposition temperature increasing from 273.7°C to 333.0°C. Differential scanning calorimetry (DSC) indicated an increased melting temperature from 311.6°C to 370.3°C and a higher melting enthalpy (ΔH) of 1179.50 J/g. Composition analysis showed 91.47 ± 1.01% cellulose and 3.73 ± 0.16% lignin content. The sequential treatment effectively produced high-purity MCC with superior crystallinity and thermal stabilities.

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